Femoral reaming system and method of performing trial reduction

ABSTRACT

An apparatus ( 10 ) for removing bone material comprises a distal cutting instrument ( 12 ) and a proximal cutting instrument ( 14 ). The distal cutting instrument has at least one first cutting edge ( 30 ), a shoulder ( 20 ), and a shaft portion ( 22 ). The shaft portion ( 22 ) has an anti-rotation feature. The at least one first cutting edge ( 30 ) removes bone material when moved in a first direction. The proximal cutting instrument ( 14 ) is removably attached to the shaft portion ( 22 ). The proximal cutting instrument ( 14 ) has a first end portion ( 68 ) and a second end portion ( 66 ). The second end portion ( 66 ) contacts the shoulder ( 20 ) of the distal reamer ( 12 ) when the proximal reamer is mounted to the shaft portion ( 22 ). The proximal reamer ( 14 ) has at least one second cutting edge ( 32 ) and an aperture. The aperture is adapted to receive the anti-rotation feature of the shaft portion ( 22 ) of the distal reamer ( 12 ). The at least one second cutting edge ( 32 ) removes bone material when moved in a second direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Applications No.60/826,675, filed Sep. 22, 2006 and No. 60/781,025 filed Mar. 10, 2006.The disclosure of each application is incorporated by reference in itsentirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

APPENDIX

Not Applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to surgical devices and, moreparticularly, to surgical devices used in long bones.

2. Related Art

Current modular implant instrument systems are such that there are twoseparate reamers provided in preparing the femoral canal. One reamer isused to prepare the distal portion of the canal. The reamer is thenremoved from the drill and the second reamer is attached to the drill toprepare the proximal portion of the canal. Such systems are laborintensive and time consuming.

Other systems build on or add to the distal reamers. In these systems,the surgeon would have to build the reamer before attaching to thedrill. The surgeon is typically required to ream with the distal reameruntil the desired distal diameter is achieved. At this point the surgeonhas to remove the distal reamer from the drill and add the proximalreamer/s from the end of the distal reamer shaft. In this system, boththe proximal reamer and distal reamer have their own depth marks toreference the greater trochanter. Neither reamer has a common referencemark between the reamers. Therefore, the reamers may still be inexact inpreparing the distal to proximal portions of the femoral canal becauseof errors such as tolerance stack and human error. With the addition ofsleeves, another tolerance (sleeve length) must be taken into accountwhen reaming the proximal depth.

Yet another example uses a combination proximal and distal reamer (orplurality of reamers) having a flexible core within the reamer to allowthe proximal portion to flex and prepare the medial side of themetaphyseal within the femur. It can also be utilized to fit more withinthe bow of the femur. This flexible core can create a series ofpotential issues. First issue is the ability to clean the tool core.With spiral cuts within the core or other means to create flexibility,the potential exists for blood, tissue, or small bone fragments to becaught within the core of the reamer. Another issue is with thepotential of the system binding such that the flexible core creates a“coiling” effect and doesn't allow the reamers to turn and cut due tomore torsional resistance of the bone cutting than torsional resistanceof the flexible core.

For a proximal reamer design, the shaft drives both the proximal anddistal reamers simultaneously. The elongated shaft guides the proximalbroach to remove the medial side of the metaphyseal. Therefore, thepurpose of having the modular proximal reamer is to have exposure forthe elongated shaft to use as a guide in broaching.

In other embodiments, the distal reamer is utilized for reaming out thedistal segment only. The surgeon disconnects the distal reamer andconnects to a proximal reamer. The proximal reamer requires a distalpilot to be attached, for guiding purposes during the preparation of themetaphyseal for the implant.

Other reamers have a trial head/neck that can be attached to a reamer orbroach for a trial reduction. The head/neck trial assembly is attachedby a handle to create the version desired. The head/neck assembly canalso be adjusted proximally or distally to select the desired height aswell. The location of the head/neck assembly relative to the reamer orbroach may be difficult to replicate with the implant. There are noreferences to locate the head/neck assembly in locating height, thus theimplant does not necessarily reflect what the surgeon measured duringthe trial reduction. The surgeon has to somewhat guess and estimatewhere the implant will be located and place the head/neck assembly tothat location accordingly.

Other systems with a distal reamer, proximal reamer, and trial neckutilize guide channels on the trial neck adaptor to establishanti-rotation and implant orientation. The proximal reamer is requiredto have straight flutes in order to have guide channels. The guidechannels dictate the cutting geometry that can be utilized for theproximal reamer. This system also does not facilitate the ability forthe proximal and distal reamers to be modular such that a surgeon canhave various proximal reamers for a given distal reamer.

There remains a need in the art for increasing accuracy while decreasingthe number of steps/instruments that is required of systems that utilizeproximal/distal reaming systems. In addition, accuracy and decreasingthe number of steps may also be achieved with respect to the method ofperforming a trial reduction for modular implant designs.

In addition, orienting the trial neck in situ without having to removethe reamer construct, especially in small incisions, may be beneficial.

SUMMARY OF THE INVENTION

In one aspect of the invention, an apparatus for removing bone materialcomprises a distal cutting instrument and a proximal cutting instrument.The distal cutting instrument has at least one first cutting edge, ashoulder, and a shaft portion. The shaft portion has an anti-rotationfeature. The at least one first cutting edge removes bone material whenmoved in a first direction. The proximal cutting instrument is removablyattached to the shaft portion. The proximal cutting instrument has afirst end portion and a second end portion. The second end portioncontacts the shoulder of the distal reamer when the proximal reamer ismounted to the shaft portion. The proximal reamer has at least onesecond cutting edge and an aperture. The aperture is adapted to receivethe anti-rotation feature of the shaft of the distal reamer. The atleast one second cutting edge removes bone material when moved in asecond direction.

In another embodiment of the invention, the at least one first cuttingedge is a right-hand cutting flute, and the at least one second cuttingedge is a left-hand cutting flute.

In another embodiment of the invention, the apparatus further comprisesa quick connect assembly. The quick connect assembly is mountable to theshaft portion and adapted to contact the first end portion.

In another embodiment of the invention, the quick connect assemblyfurther comprises a depth guide reference.

In another embodiment of the invention, the apparatus further comprisesa trial neck mountable to the shaft portion and adapted to contact thefirst end portion.

In another embodiment of the invention, the apparatus further comprisesa trial neck mountable to the distal cutting instrument.

In another embodiment of the invention, the apparatus further comprisesa trial neck mountable to the proximal cutting instrument.

In another embodiment of the invention, the proximal cutting instrumenthas a slot that extends an entire length of the proximal cuttinginstrument.

In another embodiment of the invention, the anti-rotation featurecomprises a square cross-section.

In another embodiment of the invention, the trial neck further comprisesa modular portion. The modular portion is configured to be receivedwithin the trial neck.

In another embodiment of the invention, the modular portion is furtherconfigured to have a tapered portion. The tapered portion allows foradjustment of the neck axis of the trial neck.

In another embodiment of the invention, the first cutting instrumentcomprises a broach.

In another embodiment of the invention, the apparatus further comprisesan insertion tool configured to attach the trial neck to the cuttinginstruments.

In another embodiment of the invention, the trial neck and the first endportion of the proximal cutting instrument are further configured havinga circumferential pattern of ridges and valleys. The ridges of thepattern on the trial neck are configured to mate to the valleys of thepattern on the first end portion of the proximal cutting surface.

In another embodiment of the invention, the insertion tool is furtherconfigured to rotate the trial neck relative to the distal and proximalcutting instruments.

In yet another aspect of the invention, a system for performing a trialreduction comprises a combination cutting instrument and a trial neck.The combination cutting instrument comprises a distal cutting instrumentand a proximal cutting instrument. The distal reamer has at least onefirst cutting edge, a shoulder, and a shaft portion. The shaft portionhas an anti-rotation feature. The at least one first cutting edgeremoves bone material when moved in a first direction. The proximalcutting instrument is removably attached to the shaft portion. Theproximal cutting instrument has a first end portion and a second endportion. The second end portion contacts the shoulder when the proximalcutting instrument is mounted to the shaft portion. The proximal cuttinginstrument has at least one second cutting edge and an aperture. Theaperture is adapted to receive the anti-rotation feature. The at leastone second cutting edge removes bone material when moved in a seconddirection. The modular trial neck is operatively connected to thecombination cutting instrument.

Another aspect of the invention provides a method for performing a trialreduction comprising providing a combination cutting instrument having adistal cutting instrument and a proximal cutting instrument. The distalreamer has at least one first cutting edge, a shoulder, and a shaftportion. The shaft portion has an anti-rotation feature. The at leastone first cutting edge removes bone material when moved in a firstdirection. The proximal cutting instrument is removably attached to theshaft portion. The proximal cutting instrument has a first end portionand a second end portion. The second end portion contacts the shoulderwhen the proximal cutting instrument is mounted to the shaft portion.The proximal cutting instrument has at least one second cutting edge andan aperture. The aperture is adapted to receive the anti-rotationfeature. The at least one second cutting edge removes bone material whenmoved in a second direction. The modular trial neck is operativelyconnected to the combination cutting instrument. Bone material isremoved by moving the combination cutting instruments in the firstdirection and in the second direction. A modular trial neck is attachedto the combination cutting instrument. A trial reduction of the implantis performed.

In yet another aspect of the invention, a method of preparing a longbone for an implant comprises cutting a distal portion of the long boneby moving a first cutting instrument in a first direction. Another stepprovides coupling a second cutting instrument to the first cuttinginstrument. A proximal portion of the long bone is cut by moving thecoupled cutting instruments in a second direction different from thefirst direction such that when the first cutting instrument is moved inthe second direction, the first cutting instrument does not cut thedistal portion of the long bone.

Another aspect of the invention provides a method for preparing a trialinsert for a long bone. The method comprises preparing a canal in thelong bone using at least one cutting instrument. The cutting instrumenthas the shape of the trial insert. The method also comprises adjusting atrial neck relative to the cutting instrument and coupling the trialneck to the cutting instrument. The trial neck may then be sizedrelative to the acetabulum for proper version of the trial implant.

The invention has several advantages over prior devices and techniques.First, the devices may increase accuracy while decreasing the number ofsteps/instruments that is required of systems that utilizeproximal/distal reaming systems. Increased accuracy may reduce theamount of natural bone removed from the femur and may reduce the amountof further preparation after the initial reaming In addition, reducingthe number of steps and instruments may reduce total operation time.

Second, increased accuracy and decreased number of steps may also beachieved with respect to the method of performing a trial reduction formodular implant designs, at least partially because the trial neck maybe oriented in situ without having to remove the reamer construct.

Further features, aspects, and advantages of the present invention, aswell as the structure and operation of various embodiments of thepresent invention, are described in detail below with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and form a part ofthe specification, illustrate embodiments of the present invention andtogether with the description, serve to explain the principles of theinvention. In the drawings:

FIG. 1 is an exploded view of parts of a femoral reamer according to anembodiment of the invention.

FIG. 2 is an exploded view of the parts of FIG. 1 and a quick connectassembly.

FIG. 3A is a view of a trial femoral implant including the parts of thefemoral reamer of FIG. 1.

FIG. 3B is a view of a femoral implant.

FIGS. 4A and 4B are views of trial necks according to an aspect of theinvention.

FIG. 5 is an exploded view of a distal femoral reamer and a proximalbroach according to an embodiment of the invention.

FIG. 6 is a close-up view of the distal femoral reamer and the proximalbroach of FIG. 5.

FIG. 7 is a view of an insertion tool inserting a trial into a femuraccording to an aspect of the invention.

FIG. 8 is a cut-away view of the femur of FIG. 7 showing the trial.

FIG. 9 is a view of an insertion tool according to an aspect of theinvention.

FIGS. 10A and 10B are exploded views of trial inserts and trialinsertion tools according to an aspect of the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Referring to the accompanying drawings in which like reference numbersindicate like elements, FIG. 1 is an exploded view of parts of a femoralreamer 10 according to an embodiment of the invention. The femoralreamer 10 includes two major components, a distal reamer 12 and aproximal reamer 14. The distal reamer 12 prepares the femur forreceiving a stem of a femoral implant and the proximal reamer 14prepares the femur for receiving a sleeve of a femoral implant. Thedistal reamer 12 includes a thick depth shaft 18, a shoulder 20, adistal reamer shaft 22 and a quick connect mating portion 24. The quickconnect mating portion 24 includes a mounting tip 26 and a groove 28.The quick connect mating portion 24 is attached to a drill.

The distal reamer 12 includes right-hand cutting flutes 30 while theproximal reamer 14 includes left-handed cutting flutes 32. Theright-handed cutting flutes 30 have edges on the flutes that cut in aforward cutting action when the reamer 10 is rotated. The edges of theflutes of the distal reamer 12 cuts bone in preparing the distal aspectsof the femur by connecting the reamer 10 at the quick connect matingportion 24 to a drill. The reamer 10 may cut the femur in a clockwisemanner. The surgeon will ream up (starting at smaller diameters) to thedesired distal diameter based on pre-operative templating. Inconjunction, the surgeon will ream to a depth based on the implant size.While this embodiment describes one way in which the distal and proximalreamers may be moved relative to one another, those having ordinaryskill in the art understand that other relative motions, such asswitching the directions of the flutes 30 and 32 or combining axialmotion and rotational motion may be implemented. After preparing thedistal femur, the proximal femur may be prepared.

In order to prepare the proximal portion of the femur, the distal reamer12 is disconnected from the drill and the proximal reamer 14 is attachedto the distal reamer 12. The proximal reamer 14 may be slid onto theshaft 22 of the distal reamer 12. The shaft 22 of the distal reamer 12may have a square cross-section to engage with a square aperture withinthe proximal reamer 14. The shaft 22 may transfer torque and rotationfrom the distal reamer 12 to the proximal reamer 14. The proximal reamer14 may be advanced on the distal reamer 12 until the proximal reamer 14rests upon the shoulder 20 of the depth shaft 18. The depth shaft 18sets the relative depth of the distal reamer 12 to the proximal reamer14. The depth shaft 18 may be larger in diameter in order to minimizestresses on the distal reamer 12.

In other embodiments, the cross section of the shaft 22 and the aperturein the proximal reamer 14 may be other shapes which allow the proximalreamer 14 to be coupled to the shaft 22 of the distal reamer 12. Thecross-section of the shaft 22 provides for anti-rotation of the proximalreamer 14 relative to the distal reamer 12. When the cross-section is inthe shape of a square, then there are four possible rotationalorientations of the proximal reamer 14 relative to the distal reamer 12in which the proximal reamer 14 may be seated on the shaft 22. Othercross-sectional embodiments, such as a hexagon or octagon, would have 6and 8 possible rotational orientations of the proximal reamer 14relative to the distal reamer 12, respectively. Other cross-sectionalshapes, such as a star shape, may also transfer torque and rotation tothe proximal reamer 14.

The proximal femur is prepared using the proximal reamer 14. The surgeonmay ream up (starting at a small diameter proximal reamer 14) theproximal portion of the femur by rotating the drill in acounterclockwise manner. The edges of the flutes 32 of the proximalreamer 14 are left-handed cutting flutes. When the reamer 10 is rotatedcounterclockwise, the left-handed cutting flutes 32 cut the proximalfemur. However, the distal reamer 12, when rotated counterclockwise,does not cut the distal femur because the edges of the right-handedcutting flutes 30 of the distal reamer 12 only cut the distal femur whenthe reamer 10 is rotated clockwise. When rotated counterclockwise, thedistal reamer 12 acts as a guide to prepare the proximal femoral canalminimizing additional bone being removed distally. Pre-operativetemplating may determine the final proximal reamer diameter. Inconjunction, the surgeon will ream to a depth based on the implant size.In addition, the distal reamer 12 may limit the depth of the proximalreamer 14 and act as a guide for the orientation of the proximal reamer14.

In another embodiment, the proximal reamer may include a slot that runsthrough the overall length of the proximal reamer. The slot allows theproximal reamer to be “side-loaded” onto a distal reamer withoutdisconnecting the distal reamer from the drill. In such an embodiment,the proximal reamers contain left-hand cutting flutes so that the drillmust be set to reverse in order for the proximal reamer to cut. By usinga side loading distal reamer, sizing changes between smaller diameterand larger diameter proximal reamers may also be made withoutdisconnecting the distal reamer from the drill.

A side loaded proximal reamer may be attached to the distal reamer bytwo parallel flats on the shaft of the distal reamer. The flats, incombination with the slot of the proximal reamer, allow for the proximalreamer to be indexed and locked in position with the aid of a springloaded plunger. The spring loaded plunger may overlap a portion of theproximal reamer to form an interference fit between the proximal reamerand distal reamer. While the flats may transfer torque and rotation fromthe distal reamer to the proximal reamer, an interference fit may holdthe proximal reamer in axial alignment with the distal reamer.

In operation, the combination reamer 10 allows for variable reaming sizeduring distal and proximal femur preparation, according to the size ofthe implant used in the femur. By maintaining the distal reamer positionduring proximal reaming, fewer stack errors from referencing pointsrelative to other points may be achieved. For example, angular offsetsbetween the proximal and distal portions are minimized, as well aslinear offsets such as depth or lateral movement. Any eccentricitybetween the shape of the reamer and the shape of the relief may beminimized because less jitter may result when only one of the distal orproximal reamers cuts at one time. This may result in less total boneremoval by more accurately removing only the bone necessary to remove.In addition, the orientation may allow for better placement of theimplant within the femoral canal with more uniform contact between theimplant and the natural bone.

The quick connect mating portion 24 includes the mounting tip 26 and thegroove 28. The groove 28 is an indentation in the shaft 22 and isconfigured to receive a ball bearing as described in FIG. 2. Themounting tip 26 may have a cross-section similar to the distal reamershaft 22, or may have a cross-section smaller than the shaft 22.However, the cross-section of the mounting tip 26 should be larger thanthe cross-section of the groove 28. The mounting tip 26 may be threadedso that a trial implant may be attached to the distal reamer 12. Inother embodiments, the mounting tip may be configured with otherfasteners for attaching the distal reamer 12 to the trial implant.

Turning now to FIG. 2, FIG. 2 is an exploded view of the parts of FIG. 1and a quick connect assembly 40. The quick connect assembly 40 includesan inner cylinder 42, an outer cylinder 44, a flange 46, a transversepin 48 and a drill connector 50. The inner cylinder 42 is axiallyslidable within the outer cylinder 44, and is biased at the transversepin 48. The transverse pin 48 is fixed axially to the outer cylinder 42and extends through the outer and inner cylinders 42 and 44. The pinextends through the inner cylinder 42 within a slot. The slot alsohouses a spring which biases the drill connector 50 of the innercylinder 42 axially away from the flange 46.

When the inner cylinder 42 is axially slid within the outer cylinder 44(i.e., the drill connection 50 is depressed toward the flange 46), apair of bearings are slid out of the bottom of the quick connectassembly 40. The bearings extend radially outward from the quick connectassembly 40 to a distance greater than the inner diameter of the outercylinder 44. With the bearings extending out from the inner cylinder 42,the quick connect assembly 40 is positioned to connect to the reamers 12and 14.

The proximal reamer 14 is seated on the distal reamer 12. When theproximal reamer 14 is seated on the distal reamer 12, the mounting tip26 and the groove 28 are located above the proximal reamer 14. Thus, themating portion 24 of the distal reamer 12 is positioned for attachmentto the quick connect assembly 40. The quick connect assembly 40 is slidover the mounting tip 26 and the groove 28. The bearings, extendedoutward, are slid over the groove 28. The drill connection 50 of theinner cylinder 42, then, may be axially slid away from the flange 46 andthe bearings forced into the groove 28 by the inner surface of the outercylinder 44. The inner cross-section of the inner cylinder 42 may beshaped like the cross-section of the distal reamer shaft 22 so that thetorque and rotation from the drill may be transferred from the quickconnect assembly 40 to the reamers 12 and 14.

When the quick connect assembly 40 is attached to the reamers 12 and 14,the depth of the distal reamer 12 is fixed relative to the quick connectassembly 40. The quick connect assembly 40 may secure a tight axial fitof the proximal reamer 14 between the quick connect assembly 40 and thedistal reamer 12. In addition, whether the proximal reamer 14 isattached to the distal reamer 12 does not change the depth of the distalreamer 12. Because the distance is fixed, the quick connect assembly 40,then, may also have indicator lines for each implant size on the quickconnect assembly 40. These indicator lines may reference the tip of thegreater trochanter, and may be etched into the visible portions of theinner or outer cylinders 42 and 44. Thus, the quick connect assembly 40may act as a single reference guide for both the distal reamer 12 andthe proximal reamer 14.

Turning now to FIG. 3A, FIG. 3A is a view of a trial femoral implant 60including parts of the femoral reamer of FIG. 1. The trial implant 60includes the distal reamer 12, the proximal reamer 14 and a trial neck62. The trial neck 62 is oriented relative to the reamers 12 and 14similar to the orientation of the neck of an implant. When attached tothe reamers 12 and 14, the trial neck 62 acts as an implant forcorrectly positioning the femoral component relative to the acetabularcomponent of the implant.

After proximal and distal reaming is complete, the quick connectassembly is detached from the shaft of the distal reamer 12. Theproximal and distal reamers are still located within the femoral canal.The trial neck 62 is then connected to the shaft of the distal reamer12, to the proximal reamer 14, or any combination of the two. The trialneck 62 may be angularly oriented about the axis of the femur, thusproviding the surgeon with the desired version angle for the implantprosthesis. The surgeon may then perform a trial reduction of theimplant by using the proximal and distal reamers 14 and 12 inconjunction with attaching a trial head to the trial neck 62.

The trial neck 62 may be attached to the distal reamer 12 at themounting tip. For example, a threaded connector may be used through anaperture, as shown in FIGS. 4A and 4B of the trial neck 62, to fix thetrial neck 62 to the reamers 12 and 14. When the trial neck 62 isattached, the distance from a tip 64 of the distal reamer 12 to thetrial neck 62 is fixed. Similarly, a shoulder 66 and upper flaredportion 68 of the proximal reamer 14 as well as a head 70 of the trialneck 62 are also fixed in orientation and position relative to oneanother. These positions and orientations also match the positions andorientations of an implant, as shown in FIG. 3B.

Turning now to FIG. 3B, FIG. 3B is a view of a femoral implant 80. Adistal tip 82 of the femoral implant 80, a distal shoulder 84, a flaredproximal shoulder 86, and a neck head 88 partially define the geometryof the implant 80. The geometry of the implant 80 is approximated by thetrial 62 of FIG. 3A. The proximal reamer 12 reams to a depth equivalentto the depth of the tip 82 of the implant 80. The proximal reamer 14approximates the shape of the implant 80 between the distal and proximalshoulders 84 and 86. The fixed head 88 of the implant 80 is approximatedby the trial head 70. As discussed below, the ability to orient and sizethe trial head 70 allows for proper implantation of the implant 80.

Turning now to FIGS. 4A and 4B, FIGS. 4A and 4B are views of trial necks100 and 110 according to an aspect of the invention. The trial necks 100and 110 include a poker chip mating surface 102 and 112, recessedportions 104 and 114, and cavities 108 and 118. The trial neck 100 ofFIG. 4A includes an alignment guide 106, and the trial neck 110 of FIG.4B includes a fin 116.

The poker chip mating surfaces 102 and 112 are adjustable in rotationalorientation relative to the reamers. The mating surfaces 102 and 112 areformed such that when the surfaces 102 and 112 are mated to likesurfaces on a reamer or other part of the trial implant, the ridges onthe trial necks 100 and 110 are seated within the valleys of the likesurfaces on the reamer. Similarly, the valleys on the trial necks 100and 110 are seated within the ridges of the like surfaces on the reamer.The trial neck, 100 or 110, then, may be rotated about a general centralaxis of the reamers. The patterns of the poker chip surface 102 and 112may be any general surface that allows for a plurality of positions inwhich to fix the trial neck 100 or 110 to the reamers. In addition, thepattern does not have to be complete around the cavities 108 and 118.

The cavities 108 and 118 are configured to receive a connector in orderto compress the trial necks 100 and 112 to the reamers, respectively. Aconnector, such as a T-nut, may be used to fix the trial necks 100 and110 to the threaded connector of the distal reamer. The trial neck,then, is screwed in place between the connector and the reamer. Thus,when connected by a connector, the trial neck 100 or 110 may be fixed inplace for trial reduction. The orientation of the trial neck 100 or 110may be adjusted by using a tool mated to the recesses 104 and 114 torotate the trial head 100 and 110.

The recesses 104 and 114 may be similar to a spanner head of a screw.The recesses 104 and 114 receive prongs from a tool (shown in FIGS.7-10) which may provide rotation to the trial head. By placing therecesses 104 and 114 on the periphery of the trial necks 100 and 110,minimal torque may be used to rotate the trial neck. In addition, theperipheral placement of the recesses 104 and 114 may minimizeinterference with the connector used through the cavities 108 and 118 tofix the trial necks 100 and 110 to the reamers. While the spannerhead-like design of the recesses 104 and 114 have been used in thisexample, other interfaces designed to transfer rotation and torque froma tool to the trial head 100 or 110 may be used.

The trial necks 100 and 100 may also have certain features that helporient the neck relative to the bony anatomy. Features such as thegroove 106 or fin 116 may be used as a guide to cauterize or drawreference marks on the anatomical structures or natural features toreference the position of the trial neck 100 or 110 relative to otheranatomical landmarks or structures.

Rotation of the trial neck 100 or 110 may be limited by ananti-rotational element to prevent rotation of the trial neck withrespect to the bone. The element may be a fin such as the fin 116,spike, screw, or other structure or method that engages the bone toprevent rotation of the trial neck 100 or 110. Likewise, the proximaland distal reamers may have structures or methods to prevent rotation ofthe trial implant relative to the bone. This may be accomplished by, forexample, a collar fitted over the reamers to prevent rotation, screwsprojecting into the bone, grooves that accept pins or screws placedbetween the trial implant and the bone, or any other structure or methodto prevent rotation. The methods and structures that provide rotationalalignment of the reamer may also be used as a way to match the alignmentof the implant to the trial and associated reamers.

Turning now to FIG. 5, FIG. 5 is an exploded view of a distal femoralreamer 120 and a proximal broach 122 according to an embodiment of theinvention. The broach 122 is configured to connect to an impactor tool124, which includes a handle 126 and a connector 128. The broach 122 andthe tool 124 have a cavity 130 configured to receive a shaft 132 of thedistal reamer 120. The shaft 132 aligns the proximal cutting instrument122 along the axis of the distal reamer 120. The handle 126 allows asurgeon to manipulate the broach 122 from the end of the tool 124. Theconnector 128, in this embodiment a threaded portion of the tool 124, isconfigured to receive the broach 122, or other cutting instrument.Because the broach 122 is not integral to the tool 124, the size of thebroach 122 may be changed according to the needed relief for theimplant.

The cutting instruments (the distal reamer 120 and the broach 122, inthis embodiment) provide another method of preparing a portion of thebone. Other cutting instruments such as rasps or files may be used toremove bone so that the shape in relief approximates the shape of animplant. The cutting instruments may use the distal cutting instrument(in this example, the distal reamer) as a guide. The cutting instrumentsmay prepare any number of geometries either symmetrical or asymmetrical.The instrument may have any number asymmetrical features such as spouts,fins, or bodies.

Turning now to FIG. 6, FIG. 6 is a close-up view of the distal femoralreamer 120 and the proximal broach 122 of FIG. 5. As describedpreviously, the shaft 132 of the distal reamer 120 is received withinthe cavity 130 to guide the broach 122 along the axis of the distalreamer 120. The threaded portion 128 of the tool connects the tool tothe broach 122. Cutting edges 140 of the broach 122 cut the proximalbone when the broach 122 is moved axially along the shaft 132. Thecross-section of the shaft 132, which in this embodiment is square,keeps the broach 122 from rotating. Rotation would cause an asymmetricalsection 142 to rotate and remove more bone than desired.

The cutting edges 140 of the broach 122 may be circumferential edgesseparated axially along the axis of the broach 122. The cutting edges140 may also extend around the asymmetrical portion 142 of the broach122 to allow for cutting an asymmetrical relief into the bone. While thecutting edges of the broach 122 in this embodiment are circular, otherpatterns for the cutting edges, such as spiral edges, may be used on thebroach 122.

Turning now to FIG. 7, FIG. 7 is a view of an insertion tool 150inserting a trial 152 into a femur according to an aspect of theinvention. The insertion tool 150 includes an outer member 154 and aninner member 156. The outer member 154 includes prongs 158 configured torotate the trial. The tool 150 may reference the position or version ofthe trial neck to the bone with the position and orientation of theprongs 158. Features may reference certain anatomical landmarks orprepositioned landmarks such as cautery marks or pin anchors, or toinstruments either part of the construct or in the surgical field.

The inner member 156 includes a portion configured to fix the trial 152to the reamers. The portion of the inner member 156 may include a driverhead configured to interface with a screw head on the trial 152. Aspreviously described, the screw head would connect to the mounting tipof the distal reamer through the cavity in the trial neck to fix thetrial neck 152 to the reamer.

The prongs 158 of the outer member 154 attach to the recesses on thetrial head to rotate the trial neck 152 within the femoral canal. Inorder to adjust the trial neck 152, the tool 150 is used to release thetrial neck connection from the reamer. The tool 150 may hold,reposition, and reconnect the trial neck 152. Likewise the tool 150 mayalso introduce or remove the trial neck from the surgical field.

Turning now to FIG. 8, FIG. 8 is a cut-away view of the femur of FIG. 7showing the trial. 160. The trial 160 is axially aligned through thedistal reamer 162, the proximal reamer 164, the trial neck 166 and theinsertion tool 168. The relative orientation of the insertion tool 168to the reamers 162 and 164 sets the version and orientation of the trialneck 166 for the trial 160. Thus, the trial 160 may be made up of thereamers 162 and 164 and a trial neck 166, allowing for a modular sizing,versioning, and orienting of the implant by allowing multiple sizes oftrial heads and versions of trial heads in a single step.

Turning now to FIG. 9, FIG. 9 is a view of an insertion tool 170according to an aspect of the invention. A distal reamer 172, a proximalreamer 174 and a sleeve impactor ring 176 are aligned with the tool 170.Prongs 180 impact the impactor ring 176, which would impact a proximalsleeve. A trial neck may also be attached to the modular implant sleeveimpactor 176, for example through a quick connect assembly to the sleeveimpactor 176. By disconnecting the impaction portion of the sleeveimpactor 176, the trial neck may be connected. Thus, the surgeon canperform a trial reduction including a proximal sleeve implant.

Turning now to FIGS. 10A and 10B, FIGS. 10A and 10B are exploded viewsof trial inserts 201 and 211 and trial insertion tools 200 and 210according to an embodiment of the invention. The trial inserts include atrial neck 202 and 212, a proximal reamer 204 and 214, distal reamer 206and 216, and a connector 208 and 218. The trial 211 also includes amodular member 220 having a tapered portion 222 for insertion into thetrial neck 212. The connectors 208 and 218 fix the trial neck 202 and212 to the distal reamers 206 and 216 at the mounting tips 230 and 240.

In order to fine tune the anatomical fit of an implant, the modularmember 220 is mated with the trial neck 218. The tapered portion 222 mayadjust the geometrical length, height or angulation of the neck axis inorder to restore the patient's anatomical kinesthetics. The taperedportion 222 may also have features that orient the neck relative to thebony anatomy, as mentioned above. The modular member 220 may be used oneither an implant or trial.

The method of preparing the femoral canal includes attaching a distalcutting instrument to a drill. The cutting instrument is inserted intothe IM canal and the distal portion is shaped by moving the distalcutting instrument in a first direction. When the distal portion issufficiently shaped, then the drill is disconnected from the distalcutting instrument, and the distal cutting instrument may remain withinthe IM canal. A proximal cutting instrument is placed onto the distalcutting instrument over the shaft of the distal cutting instrument. Thedrill is then attached to the cutting instrument. In one embodiment, thedrill is attached to the distal cutting instrument through a quickconnect assembly. The proximal portion of the canal is shaped, and thecanal may then be properly sized for an implant.

The method of preparing a trial insert includes shaping a distal portionby moving a first cutting instrument in a first direction and a proximalportion of a femur by moving a second cutting instrument in a seconddirection. A trial neck is attached to one of the cutting instruments.The trial neck is rotationally adjustable relative to the cuttinginstruments. A head of the trial neck may also be adjustable relative tothe trial neck to adjust the version of the trial neck.

In view of the foregoing, it will be seen that the several advantages ofthe invention are achieved and attained.

The embodiments were chosen and described in order to best explain theprinciples of the invention and its practical application to therebyenable others skilled in the art to best utilize the invention invarious embodiments and with various modifications as are suited to theparticular use contemplated.

As various modifications could be made in the constructions and methodsherein described and illustrated without departing from the scope of theinvention, it is intended that all matter contained in the foregoingdescription or shown in the accompanying drawings shall be interpretedas illustrative rather than limiting. Thus, the breadth and scope of thepresent invention should not be limited by any of the above-describedexemplary embodiments, but should be defined only in accordance with thefollowing claims appended hereto and their equivalents.

1. A system for removing bone material, the system comprising: a. adistal cutting instrument, the distal cutting instrument having at leastone first cutting edge, a shoulder, and a shaft portion, the shaftportion having an anti-rotation feature, and wherein the at least onefirst cutting edge removes bone material when moved in a firstdirection; and b. a proximal cutting instrument removably attached tothe shaft portion, the proximal cutting instrument having a first endportion and a second end portion, the second end portion contacting theshoulder of the distal reamer when the proximal reamer is mounted to theshaft portion, the proximal reamer having at least one second cuttingedge and an aperture, the aperture adapted to receive the anti-rotationfeature, and wherein the at least one second cutting edge removes bonematerial when moved in a second direction.
 2. The system of claim 1,wherein the at least one first cutting edge is a right-hand cuttingflute, and the at least one second cutting edge is a left-hand cuttingflute.
 3. The system of claim 1, further comprising a quick connectassembly, the quick connect assembly mountable to the shaft portion andadapted to contact the first end portion.
 4. The system of claim 3,wherein the quick connect assembly further comprises a depth guidereference.
 5. The system of claim 1, further comprising a trial neckmountable to the shaft portion and adapted to contact the first endportion.
 6. The system of claim 1, further comprising a trial neckmountable to the distal cutting instrument.
 7. The system of claim 1,further comprising a trial neck mountable to the proximal cuttinginstrument.
 8. The system of claim 1, wherein the proximal cuttinginstrument has a slot that extends an entire length of the proximalcutting instrument.
 9. The system of claim 1, wherein the anti-rotationfeature comprises a square cross-section.
 10. The system of claim 1,wherein the trial neck further comprises a modular portion, the modularportion configured to be received within the trial neck.
 11. The systemof claim 1, wherein the modular portion is further configured to have atapered portion, the tapered portion allowing for adjustment of the neckaxis of the trial neck.
 12. The system of claim 1, wherein the firstcutting instrument comprises a broach.
 13. The system of claim 12,further comprising an insertion tool configured to attach the trial neckto the cutting instruments.
 14. The system of claim 12, wherein thetrial neck and the first end portion of the proximal cutting instrumentare further configured having a circumferential pattern of ridges andvalleys such that the ridges of the pattern on the trial neck isconfigured to mate to the valleys of the pattern on the first endportion of the proximal cutting surface.
 15. The system of claim 14,wherein the insertion tool is further configured to rotate the trialneck relative to the distal and proximal cutting instruments.
 16. Amethod for preparing a femoral canal, comprising the steps of: a. movinga first cutting instrument in a first direction thereby cutting a firstportion of bone; b. attaching a second cutting instrument to the firstcutting instrument; and c. moving the first and second cuttinginstruments in a second direction different than the first directionthereby cutting a second portion of bone.
 17. The method of claim 16,wherein the first and second directions are clockwise andcounterclockwise rotation.
 18. The method of claim 16, wherein the firstand second cutting instruments do not cut the first portion of bone whenthe first and second cutting instruments are moved in the seconddirection.
 19. The method of claim 16, further comprising the step ofattaching a trial instrument to at least one of the first and secondcutting instruments.
 20. The method of claim 19, further comprising thesteps of: rotating the trialing instrument relative to at least one ofthe first and second cutting instruments; and fixing the trialinginstrument to at least one of the first and second cutting instruments.